These examinations were carried out on four separate periods occasions. Sonomatic used the well proven Microplus system and Nautilus Subsea Manipulator to collect and display the data.

Two techniques were deployed, Pulse Echo (PE) and Time of Flight Diffraction (Tofd). The PE method was used to collect thickness measurement and generate high-resolution maps of each site inspected. Tofd was then used to collaborate the PE findings and to aid in through wall characterisation of the flaws.

The high-resolution scans were taken using the Nautilus Subsea scanner, which facilitates the very precise positioning, and movement of the ultrasonic transducers. Saturation divers working at a depth of 450ft installed the scanner on the site.

All four inspections were then used to apply Fitness for Service calculations and assessing remaining life of the pipeline.